1. Field of the Invention
The invention concerns a sealing profile, in particular for windows, doors or the like, including a holding section on the base, pedestal, foot or bottom side (in the following defined and used as xe2x80x9cbottom sidexe2x80x9d) of the sealing profile with at least one holding means provided for engaging in a receptacle, and a sealing section joined to the holding section. The holding means is formed by a leg-like web portion which comprises a projecting holding lip and which is linked articulately to a wall extending longitudinally with the sealing profile and forming a bottom trunk of the holding section. The web portion yields against an elastic material return force as a result of insertion in the receptacle. Seals of the kind mentioned can be used for a number of applications. They serve preferably to seal off a window casement from a window frame or a door leaf from a door frame. They prevent the entry of air and/or moisture through the element to be sealed and additionally act as sound insulation.
2. Prior Art
To obtain a high sealing effect, known sealing profiles are made, at least in part, of soft material. Soft elastic materials are however relatively costly. Therefore non-sealing regions are made of harder cheaper material. Thus seals are known (DE-U1-296 09 976) in which regions which assume a sealing function are made of thermoplastic elastomers (TPE) and other regions are made of ethylene vinyl acetate (EVA). Known sealing profiles also have tension-resistant inlays (e.g. DE-U1-9402689.0, EP-A1-0436810). The inlays serve to take up tensile forces which arise during seal assembly, and they limit the elongation, namely stretching of the profile. The tension-resistant inlays are usually made from wires or textile, polyester or cotton threads. The wires and threads impede reuse and recycling of the sealing profile material, as the material components are not compatible and it is uneconomical to separate them for recycling.
Also known are sealing profiles (e.g. DE-U1-9402689.0, EP-A1-0436810) which are provided with a reinforcing rear wall made of a material which is substantially harder than that of the remaining extruded seal. The hard wall is intended to prevent bending on insertion of the seal in the receptacle and to form a sliding aid for introduction into the receptacle. The hard wall must be clamped fast enough against the receptacle wall by at least one holding lip. For this purpose the articulated link of the sealing lip is to be relatively stiff. In order to facilitate insertion of the seal in the receptacle, however, internal recesses are provided in the region of the link (DE-U1-9402689.0). This leads to weakening of the clamping action and consequently unwanted release from the receptacle groove. This is countered by the fact that several holding lips are provided.
Another known sealing strip consisting of a solid profile is formed from elastic soft plastic foam which is coated with a water-repellent layer (U.S. Pat. No. 4,535,564). To fix the sealing strip in a groove, an anchor section formed from the plastic foam is embedded in a hook-like strip. The hook strip is made of a material which is less compressible than the plastic foam. It is intended to give the anchor section strength and to facilitate introduction of the anchor section into an anchor groove. Here the hook strip filled with the elastic spring plastic material is compressed for insertion. The receptacle groove is provided with an additional recess in which a leg of the hook strip is to be engaged under relaxation. Manufacture of the sealing strip with such a hook strip is elaborate. There is a risk of the sealing strip being destroyed on removal from the groove, as the leg of the hook strip which springs open is caught in the associated recess.
It is the object of the invention to provide a sealing profile which is to be improved particularly with regard to assembly, sealing function, remaining in the profile receptacle, dimensional stability as well as easy, cheap and environmentally friendly manufacture.
This object is achieved according to the invention in combination with the characteristics of the sealing profile of the kind mentioned in the introductory portion, in that the web portion on its side facing towards the associated receptacle is provided with at least one layer extending in the longitudinal direction and transversely to the direction of insertion of the sealing profile and assisting sliding insertion of the web portion into the receptacle. This layer is made of a material harder than the material of the web portion which is provided with the layer, wherein the web portion in the top contact region of the projecting holding lip with the receptacle is free from the hard layer and the hard layer acts as a rigid pivot element, which in at least one zone of the softer material of the web portion makes it hard for the web portion to expand. Thus a number of advantages are obtained. The hard layer provided and arranged according to the invention promotes compression of the web portion, so that a critical reduction of resistance is brought about on insertion of the sealing profile into the associated profile receptacle. The sealing profile passes without the use of lubricants such as silicone oil or the like particularly smoothly with optimum sliding action into the profile groove. The layer of hard material which is continuous over the length of the seal serves as a so-called stretch brake in the form of a hard material core which is integrated in the soft material of the web and which during and after assembly reliably prevents elongation and unwanted deformation of the profile strand. The layer-free web material and the sealing material are substantially more extendible in the longitudinal direction of the profile than the hard layer of the web. As a result of a convex curvature of the profile strand in the longitudinal direction, which convex curvature inevitably forms, insertion in the profile groove with a kind of snap action is promoted. The hard layer of the web which is strip-like over the length of the profile strand, owing to its upright geometry in a direction transversely to the linking wall, ensures high torsion resistance of the profile in the region of the holding lip which makes the clamping connection in the receptacle. On the whole, considerable handling and functional advantages are gained, particularly when mechanically crimping the sealing profile into a profile receptacle. The web portion bridges the profile cross-section of the receptacle in the form of an articulately linked leg. The link region and the leg, which is pivotable about the link region, are shape-retaining, shape-giving parts of the seal. The material of the joint region determines the spring behavior of the linked leg. Here, a significant additional combination effect of the strip-like hard layer of the web lies in that inward expansion/compression of the leg portion when inserted/pressed into the receptacle is substantially easier than outward/upward expansion under tensile stress against the direction of insertion or on removal from the profile receptacle. On account of this marked directional characteristic, the holding section fits snugly and stably in abutment and sealing in the profile receptacle. The hard layer of the web, in the state of the holding section inserted in the associated receptacle, causes a kind of anchorage which considerably improves the sealing fit and sealing stability and function. The hard layer of the leg web which forms an arm-like rigid pivot element acts in connection with the softer leg material as a transversely tilting pressure bar whose compression resistance increases with increasing expansion of the web leg. This is possible due to the fact that, on tilting of the strip-like hard layer, the softer material of the web leg is upset much more in edge and end regions of the hard layer than in its central region. Due to the particular location of applying the hard layer, the anchoring effect depends particularly markedly on the quantity and direction of the force acting on the web portion. Simply by this means is increased adhesion and sealing action of the seal bottom in the associated profile receptacle achieved. With the hard layer of the web, the sealing profile according to the invention is also particularly easy to make, obtaining material savings which lead to cheap manufacture. Not least, particularly as a result of material-saving design of the seal and pronounced anchorage effect, the life and functional time of the seal are increased. But, on the other hand, the compression of the softer material obtained according to the invention on exceeding a given quantity of tensile force acting counter to the direction of insertion also allows non-destructive release of the sealing profile from the profile receptacle.
Advantageously, insertion of the sealing profile in the profile receptacle is promoted not only by the hard layer surface in combination with the softer material of the web portion, but also by the fact that the hard layer on the lower surface of the holding bottom is exposed with a sliding surface.
Particularly advantageously, the holding means of seals according to the invention are constructed as lip and/or cavity profiles by contrast with solid profiles. The web leg portions provided with the hard layer yield during inward compression and upward expansion into material-free space. The groove between the leg portion provided with the hard layer and the wall linking it is free from material, so that on the one hand, inward expansion/compression of the holding leg is promoted, while on the other hand, by means of the selected extent of the hard layer, the upset region in the softer web material is precisely defined and fixed.
In a particularly preferred embodiment of the invention, the web portion is formed by a cavity bottom of arrow-shaped profile. Two leg portions arranged in a V shape and linked each to an associated profile wall and each provided with the hard layer adjoin each other in the region of the arrow-shaped apex. Under the effect of the expansion force, the adjoining portions made of the soft web material are forced against each other by means of the strip-like arm-like hard layers, so that an upset zone counteracting the expansion to a particular extent is formed. Upsetting of the material in the transition region between the two legs can appropriately be provided to a particularly marked extent by the fact that the bottom surface of the holding bottom in the region of the arrow-shaped peak is free from the hard layer.
With known cavity-bottom seals, it is frequently necessary to apply to the whole of the holding section a sliding layer and in particular lubricants such as glycerol or silicone. The use of lubricants is not only cost-intensive and labor-intensive, but also there is a risk of damage to health, and the lubricants pollute the environment. Also, use of the lubricants can impair the sealing action. In case of frequent stress as well as due to environmental effects, e.g. due to humidity, dust and temperature, the sealing fit can be impaired, and there is a risk that the sealing profile will come out of its profile receptacle undesirably, so that disadvantageous sealing gaps arise and also operation of the windows, doors, etc. provided with the sealing profiles is considerably impaired. Such drawbacks are also eliminated by the cavity bottom according to the invention.
In order to produce a progressive anchoring force transversely to the bottom trunk of the sealing profile with the hard layer laid transversely, it is also particularly appropriate to link the holding web portion to a wall which essentially in the central region of the hard layer formed on the web portion is joined to the hard layer by the softer web portion material carrying it.
In another embodiment of the invention, the holding section and the sealing section are joined together by a profile spine, wherein the profile spine is preferably provided with a spine layer which extends as far as the bottom end and which is harder than the spine material of the seal provided with the spine layer. Particularly advantageously, the transition region between the lower side of the web portion and the profile spine remains free from the web portion hard layer.
In all embodiments of the invention, appropriately, the free side end of the web portion forming the holding lip is provided free from the hard layer. It is particularly appropriate, especially for holding lips of an arrow-shaped holding bottom in connection with profile receptacles in metal or plastic elements, that the free end of the web portion forming the holding lip is made of thermoplastic elastomer (TPE), so that it has a braking action against being pulled out.
In an appropriate embodiment, the holding lip, seen in profile cross-section, is provided with at least two holding tips which butt against an associated receptacle wall, wherein a lower holding tip comprises the hard layer and preferably springs back relative to a holding tip above it in the unstressed state.
It is particularly advantageous that the hard layer of the holding web portion can be constructed as a wafer-like layer which is thin compared with the profile thickness of the web portion provided with the hard layer and which is exposed on the lower surface of the bottom.
Preferably, the hard layer is a polyolefin, preferably a polyethylene, the softer portions of the seal being formed from thermoplastic elastomers (TPE). Thus, particular profiles which are ready to assemble can be made by coextrusion in one operation. The bottom hard layer can be applied selectively and partially as well as locally with precision at the points at which it performs the functions described. The material combination described also ensures high dimensional stability and hence a high sealing effect. It is also particularly advantageous that the seal material with all its components can be reused as a recycling product in the form of ground material. Preferably an adapted softer material is added for use with the desired hardness. The recycling product is available cheaply and allows environmentally friendly manufacture.
Subsidiary claims are also aimed at other appropriate and advantageous embodiments of the invention.